condennnsa
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what is this stuff?
So I was searching the internet for methods of breaking concrete, and accidentally came upon this:
http://www.archerusa.com/
I didn't know that stuff like this existed and can create such huge pressure to break reinforced concrete safely.
I looked up this dexpan's msds and it says it contains 60-100% Ca(OH)2 , but it doesn't make sense... as far as I know Ca(OH)2 only dissolves in water
to a minor degree, and provided there is CO2, it will slowly turn to calcium carbonate, right?
How does it expand when combined with water so fast (max 24 hours) and create such huge pressure?
Here is a video of it in action
http://www.youtube.com/watch?v=YlDQvgM4pKM
the MSDS:
http://www.archerusa.com/nonexplosivesblastingdemolition/dex...
Is this really Ca(OH)2?
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White Yeti
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Hmm...
You're right, Ca(OH)<sub>2</sub> doesn't make sense, there must be another component to that mixture. It might react with dissolved carbon
dioxide in the water, but there's no way that reaction can happen over as little as 24H.
I can't help but think this is a scam of some kind.
"Ja, Kalzium, das ist alles!" -Otto Loewi
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UnintentionalChaos
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Quote: Originally posted by White Yeti  | Hmm...
You're right, Ca(OH)<sub>2</sub> doesn't make sense, there must be another component to that mixture. It might react with dissolved carbon
dioxide in the water, but there's no way that reaction can happen over as little as 24H.
I can't help but think this is a scam of some kind. |
No, I've used it before...I'm not sure what the stuff is, but it certainly works.
Department of Redundancy Department - Now with paperwork!
'In organic synthesis, we call decomposition products "crap", however this is not a IUPAC approved nomenclature.' -Nicodem
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neptunium
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is it the kind of reaction like water freezing increases its volume hence craks the glass?
hence the "stuff" disolves slowly in water increassing its volume dramaticaly and bang! cracks the concret??
just a wild guess...
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Adas
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Sodium polyacrylate increases volume massively when soaking water. It can absorb very much water (1000 times more than own weigth/volume ??)
EDIT: Not sure if it can break concrete, though.
[Edited on 25-1-2012 by Adas]
Rest In Pieces!
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neptunium
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yeah seems like a long shot ....
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MrHomeScientist
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Yeah there's no way sodium polyacrylate would break anything. While it does expand, it turns into a gel when a lot of water is used and a snow-like
consistency with less water. Either way, it's very compressible and I really doubt it would exert enough force to do anything.
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Lambda-Eyde
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It's most likely calcium oxide, CaO. A similar product is sold where I live which contains relatively pure CaO.
Edit: Turns out I wasn't completely correct - the product above contains 10-30 % aluminate cement and 60-80 % CaO according to the MSDS. The package
says 60-100 % CaO, IIRC.
[Edited on 25-1-2012 by Lambda-Eyde]
This just in: 95,5 % of the world population lives outside the USA
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neptunium
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judging by the gnome pushing against rocks with his elbow it must be strong stuff!!!!
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condennnsa
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You're right, Lambda-Eyde, i did more searching on calcium oxide expansive mortar and found this paper http://arxiv.org/ftp/arxiv/papers/1107/1107.0074.pdf which makes it clear that it is the hydration of CaO doing all the work.
It pisses me off, why would a producer claim in the material SAFETY datasheet that their product contains Ca(OH)2, which is a mostly inert chemical,
instead of the truth, CaO, which is very corrosive and dangerous in moist environments... ?!
I have never worked with CaO, and don't have any but I wound have thought that upon mixing it with water it would heat up, but continue to stay as a
slurry and not 'set'.. there must be some strong interlocking of Ca(OH)2 crystals going on..
I have an electric furnace that i got to 800C I'll try and dehydrate some Ca(OH)2 which wiki says it takes 512C , going to check water loss by weight
difference
[Edited on 26-1-2012 by condennnsa]
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GreenD
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This would be great with a long drill on some train bridge pillars.
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